Attempts have been made in the technical development for commercializing flat panel display devices which use OLEDs to prevent moisture-caused deterioration of OLED characteristics, and to partly solve problems involved in means for securing mechanical strength associated with flat panel display devices. For example, JP-A-9-148066 discloses use of a desiccant; JP-A-8-236271 discloses a structure with a gap between a substrate which constitutes an OLED and encapsulating can (or plate) filled with a rubber elastomer to prevent inflow of moisture; JP-A-5-182759 discloses a structure with a gap between a substrate which constitutes an OLED and encapsulating plate filled with an UV curing resin; and JP-A-2001-68266 discloses a structure with a gap between a substrate which constitutes an OLED and encapsulating can filled with a desiccant-containing gel component.